Through-cradle soft tissue biopsy device

Abstract

Among other things, there is disclosed a biopsy needle having a cutting cannula axially slidable over an inner stylet. The inner stylet has a proximal portion connected to a distal portion that includes first and second spaced-apart struts. The distal portion has a tissue penetrating tip and the stylet defines a sample-containment space between the struts having first and second radially opposed lateral openings thereto. The sample-containment space of the stylet readily accepts tissue through either of the lateral openings such that a near full core of tissue can be sampled.

What is claimed is: 
     
       1. A biopsy needle, comprising:
 an external tubular member having an internal lumen and a sharpened distal end; 
 an internal member defining a central longitudinal axis and having a proximal portion connected to a distal portion, said distal portion including first and second spaced apart struts along a sample-containment space through which the axis extends and a tissue penetrating tip, said first strut having first and second edges adjoining a first surface facing the axis and said second strut having third and fourth edges adjoining a second surface facing the axis, said first and second surfaces forming a boundary of said sample-containment space, said sample-containment space having first and second radially-opposed lateral openings wherein the first lateral opening is bounded by the first and third longitudinal edges and the second lateral opening is bounded by the second and fourth longitudinal edges; and 
 wherein said internal member is slidably positioned within said lumen of said external member between a first relative position in which said sample-containment space and lateral openings are at least partially extended from said external member, and a second relative position in which said sample-containment space and lateral openings are entirely within said lumen. 
 
     
     
       2. The biopsy needle of  claim 1 , wherein said first and second surfaces are concave. 
     
     
       3. The biopsy needle of  claim 2 , wherein said concave surfaces are uniform along the respective lengths of said first and second struts, and each form a portion of a cylinder centered on said central longitudinal axis. 
     
     
       4. The biopsy needle of  claim 1 , wherein said tissue penetrating tip is in a longitudinal plane defined by said first and second struts. 
     
     
       5. The biopsy needle of  claim 1 , wherein said first and second openings have approximately the same length measured along said longitudinal axis. 
     
     
       6. The biopsy needle of  claim 1 , wherein said first opening has a larger length measured along said longitudinal axis than said second opening. 
     
     
       7. The biopsy needle of  claim 6 , wherein said first opening subtends an arc of the perimeter of said inner member that is more than 180 degrees. 
     
     
       8. The biopsy needle of  claim 7 , wherein said arc is approximately 200 degrees. 
     
     
       9. The biopsy needle of  claim 8 , wherein a plane defined by the middles of said first and second struts is offset from said longitudinal axis. 
     
     
       10. The biopsy needle of  claim 1 , wherein said distal portion of said inner member includes first and second end surfaces bounding said space, said end surfaces contacting each of said struts and being oblique to said longitudinal axis. 
     
     
       11. The biopsy needle of  claim 10 , wherein said first and second end surfaces are substantially planar across a diameter of said internal member. 
     
     
       12. The biopsy needle of  claim 10 , wherein said first and second end surfaces point toward each other, so that said first and second radially-opposed lateral openings have different lengths and/or different widths. 
     
     
       13. The biopsy needle of  claim 1 , wherein said inner member is a tubular member having an inner diameter, and said first and second surfaces are part of said inner diameter of said tubular member. 
     
     
       14. The biopsy needle of  claim 1 , wherein said inner member is a solid non-hollow member, so that the portions of said inner member adjacent said sample-containment space are filled in. 
     
     
       15. The biopsy needle of  claim 1 , wherein said external member defines an inner circumference and an outer circumference and first and second cutting edges for cutting across the first and second side openings respectively. 
     
     
       16. The biopsy needle of  claim 1 , wherein the sample-containing space is unobstructed so that a sample may be removed from said space by passing through either of said first and second lateral openings. 
     
     
       17. The biopsy needle of  claim 1 , wherein at least one of said edges can guide tissue past such edge and into said sample-containing space.